The present invention generally relates to weapon systems, and, more specifically, concerns a new and improved construction of apparatus for generating an electrical ignition current in the fuze of a projectile which is intended to be fired from a weapon or gun. Generally speaking the apparatus of this invention is of the type comprising an induction coil located in the projectile, a magnet for generating a magnetic field, a two-part or bipartite yoke, one part of which is located at the projectile and the other part of which is located at the weapon barrel, in order to generate a change in the magnetic flux upon passage of the projectile through the weapon barrel.
According to a state-of-the-art construction of apparatus of this type, as disclosed in U.S. Pat. No. 1,739,921, an electromagnet is arranged at the mouth or muzzle of the weapon barrel and the projectile fuze possesses an induction coil. Upon passage of the induction coil through the electromagnet there is induced a current in the induction coil which, on the one hand, is employed for charging a capacitor and, on the other hand, for switching-on a mechanical timing relay.
Disadvantageous with this prior art construction is the need to arrange an electromagnet at the muzzle at the region of the hot gases, and further, with such electromagnet there can only be induced a single current surge.
Furthermore, there is known to the art from U.S. Pat. No. 3,417,700 an apparatus where a number of induction coils containing permanent magnets are uniformly distributed at the circumference or periphery of the projectile body, and the coil axes are disposed radially with regard to the projectile body. The magnetic field produced by the permanent magnets is closed as long as the projectile is located within the weapon barrel and opens as soon as the projectile departs from the weapon barrel, resulting in a voltage being induced in the induction coil.
Yet this prior art apparatus is associated with the following drawbacks:
(a) such type arrangement of the induction coils cannot be employed with small caliber ammunition; PA1 (b) the radial acceleration in the case of spinning ammunition does not allow for any such type arrangement of the induction coil; and PA1 (c) there can only be generated a single pulse. PA1 (a) the part of the yoke located at the weapon barrel possesses a number of ferromagnetic rings or ring members; PA1 (b) paramagnetic rings or ring members are arranged between the ferromagnetic rings; PA1 (c) the part of the yoke located at the projectile body comprises a substantially cylindrical body member having a substantially disc-shaped flange for the reception of the induction coil as well as a soft iron disc; PA1 (d) the magnet in the form of a permanent magnet is arranged between this substantially cylindrical body member and the soft iron disc; PA1 (e) the axis of the induction coil substantially coincides with the projectile axis; and PA1 (f) the aforesaid ferromagnetic rings and paramagnetic rings are arranged at the end of the weapon barrel. PA1 (a) the magnet comprises an electromagnet located at the mouth of the weapon barrel and composed of a number of ferromagnetic rings and paramagnetic rings arranged between the ferromagnetic rings; PA1 (b) the part of the yoke at the weapon barrel comprises a three-arm yoke attached to said ferromagnetic rings; PA1 (c) two electromagnetic coils polarized in opposite directions surround at least part of said three-arm yoke; and PA1 (d) the axis of the induction coil substantially coincides with the axis of the projectile.